Learn more about the fascinating functions of hydrodynamic mechanisms and hydraulics in nature.

Vital Functions Of Hydrodynamic Mechanisms

Posted: December 18th, 2009 | Filed under: Extra unnatural functions | Tags: , , , , , , | No Comments »

Hydrodynamic mechanisms are also very good for digĀ­ging burrows. When tunnelling through moist soil, the earthworm contracts the circular muscles at its front end to the utmost. Thus, its head becomes a kind of a sharp awl (if the soil is dry the worm moistens it). Then it looks for some tiny gap between the particles of soil. If it fails to find one, the worm drives its front end into the earth by delivering blows against it from the inside with the aid of its gullet which is operated by a hydrodynamic mechanism. An increase in pressure from 2 to 14 millimetres of the water column allows it to strike blows with a force of 8.5 grams. As soon as the earthworm succeeds in burrowing itself to some depth, it increases the pressure in the front end, making it swell out and thus widen the burrow. If the soil is not very hard, the earthworm will, by repeating this operation, bury itself in the soil before our very eyes. Still more energetic are sipunculids which, when digging their burrows, develop a pressure of up to 600 millimetres of the water column.

Among the most perfect hydrodynamic mechanisms is the locomotion device found in the Echinodermata which is particularly well developed in the starfish, sea-urchins, brittle stars and various sea cucumbers. The arms of the starfish are permeated with symmetrically radiating grooves filled with a watery fluid. Small branches extending from the grooves enter each of the numerous tube feet located on the under surface of the arms. When the starfish moves, the fluid is forced into the tube feet making them swell out and stretch in the direction in which it is moving; after the tube feet get a foothold by means of the suckers on its arms their muscles contract forcing the fluid from the grooves and thus helping the starfish to crawl forward a little. Then the tube feet detach from the ground on which the starfish is moving, the fluid is forced into them again, and the cycle begins anew. This shows that the heart is not the only pump employed by nature to help the organisms of various animals in performing their most vital functions.


Hypertension And Obturator Muscle Functions

Posted: December 14th, 2009 | Filed under: Extra unnatural functions | Tags: , , , , , , , | No Comments »

Nature is always striving to allot an organ certain extra unnatural functions. Although the duties of the cardiovascular system are very specific and highly responsible, it could not avoid this common plight since nature was eager to utilize the pressure in the circulation system.

Hypertension (abnormally high blood pressure) is known to be very dangerous for the organism as it may disturb the blood system and cause damage to the blood vessels. Nature, however, turned this phenomenon to advantage. Thus, the lizards, known as horned toads, inhabiting the deserts of Mexico, use the local hypertension in the blood vessels of the head as a means of defence.

Generally speaking, this phenomenon is not terribly uncommon. When the blood, under abnormally high pressure, enters the crests, spines, and other outgrowths on the head and the body, they expand, straighten out, change colour and make the animal look fearful.

This is not the only means of defence of horned toads. Nature supplied them with a wonderful mechanism: when the lizard is standing at bay, a specific muscle, known as the obturator muscle, presses against one of the major blood vessels, markedly raising the pressure in the blood vessels in the head; it proves too high for the delicate vessels in the nictitating membrane and they rupture squirting blood into the face of a predator. This unexpected shower often makes the intruder take flight. This weapon is operative within the radius of one and a half metres.

The other function of the obturator muscle is connected with moulting. The reptiles continue growing throughout their lives. Horned toads change their skin every year. Casting oil one’s clothes can sometimes be difficult. This is where the obturator muscle comes into play. When the pressure in the head vessels increases, all the blood vessels, major and minor, distend and the head expands, tearing the old skin. When the skin on the head has ruptured, the lizard simply crawls out of it through the newly formed opening.